A New Selective Mapping Scheme for Visible Light Systems

The huge bandwidth and immunity to electromagnetic interference make Visible Light Communication (VLC) systems as preferred technique for designing the physical layer of 5G applications. Unfortunately, the superimposition of multiple subcarriers in DC-biased Optical Orthogonal Frequency Division Multiplexing (DCO-OFDM) system leads to a high peak to average power ratio (PAPR). The well-accepted nondistorting PAPR reducing schemes like selective mapping (SLM) require an obligatory transmission of side information (SI) reducing the bandwidth efficiency of the system. To address these issues, a simple SI cancellation algorithm using pilots associated with channel estimation is proposed in this work. In short, the DCO-OFDM system is presented with a modified cluster architecture and each cluster is assigned with at least one pilot. Every cluster is restricted to have same phase and this idea provides the pilots to perform joint channel estimation and SI cancellation. The experimental results obtained by using Universal Software Radio Peripheral (USRP) as hardware and LabVIEW as software indicate a significant reduction in PAPR without effecting the real-time channel response.